Referring to FIG. 6 an engine 1 of an automobile includes a lubrication system that uses, among other things, an oil pan 2, an oil pump 3 and an oil strainer 4. Oil strainer 4 conducts oil 5 from oil pan 2 to oil pump 3.
Referring now to FIG. 7, oil strainer 4, in brief, comprises pipe member 6, which forms the oil path, and an umbrella-shaped member 8 attached to a lower end 6a of pipe member 6. A screen 7 covers the lower end of umbrella-shaped member 8.
Screen 7 prevents impurities in the oil 5 from being sucked in, and umbrella-shaped member 8 holds this screen 7 to prevent air from being sucked in when the surface of the oil in oil pan 2 is tilted.
An enlarged view of the connection between pipe member 6 and umbrella-shaped member 8 is shown in FIG. 8. An axially directed cylindrical connection flange 9 is formed in the upper center of umbrella-shaped member 8. Lower end 6a of pipe member 6 is inserted into connection flange 9 in the upper part of umbrella-shaped member 8. After insertion, reinforcement 10, which has an L-shaped cross-section, is slid down from its initial position on pipe member 6 onto connection flange 9 and the upper part of umbrella-shaped member 8. The upright upper end of reinforcement 10 is joined integrally to the outer circumference of the upper end of connection flange 9 and of pipe member 6 by means of weld W1. The upper part of umbrella-shaped member 8 and the horizontal part of reinforcement 10 are joined integrally by means of spot weld W2.
Reinforcement 10 serves not only to join pipe member 6 and umbrella-shaped member 8 but also to form a seal between pipe member 6 and umbrella-shaped member 8. That is, reinforcement 10 is attached in order to improve the seal of oil strainer 4 and in order to improve the strength.
As shown in FIGS. 6 and 7, an upper end 6b of pipe member 6 includes a flange 11 for attachment of pipe member 6 to oil pump 3. A notch or groove 13 in flange 11 adjacent upper end 6b accommodates an 0-ring 12. 0-ring 12 seals upper end 6b of pipe member 6 to an oil pump case 14 of oil pump 3.
An oil gauge 18 is inserted into a level gauge guide 17 which passes alongside a cylinder block 15 and cylinder head 16. An end 18a of oil level gauge 18 extends into oil 5 in oil pan 2. As is conventional, oil level gauge 18 includes graduations thereon to indicate the level of oil 5 in oil pan 2.
A cylinder head bolt 19 is one of many that join cylinder block 15 and cylinder head 16. A chain adjuster 20 is disposed within cylinder head 16 to adjust the tension on a chain (not shown) for connection to oil pump 3. Oil is pumped under pressure by oil pump 3 though an oil filter and a main gallery to cylinder head 16. The oil is diverted around the circumference of cylinder head bolt 19, to chain adjuster 20. An oil pressure switch 21 monitors oil pressure. An oil drain hole 22 permits draining oil 5 from oil pan 2.
Examined patent HEI 7-4631 1995! discloses a crimping member and crimping structure. In what is disclosed, a crimping part is provided that has a cylindrical part, a flange, part of whose circumferential wall is plastically deformed. A notch is formed in a flange on one end of cylindrical part. The cylindrical part is inserted through a connection hole formed in a correspondent member to be joined to this crimping member. The notch is fitted into a notch fitting part formed on the correspondent member. The part that passes through the connection hole of the cylindrical part is plastically deformed. The correspondent member is crimped with this plastically deformed part and the flange.
Examined utility model HEI 5-22344 1993! discloses an anchoring structure for a first plate and second plate that employs a crimping cylinder on the second plate fitted rather tightly onto the outer circumference of a cylindrical protrusion on the first plate. Striking pressure is applied to the upper end face of this crimping cylinder and cylindrical protrusion to form flat ribs on the cylindrical protrusion. Rib crimping surrounds the flat rib in the crimping cylinder, thereby holding in place the first plate and second plate.
Unexamined utility model SHO 58-71422 1983! discloses a fence in which the ends of a steel plate are crimped and both ends of multiple pipe-shaped upright crosspieces are fitted into cylindrically flanged through-holes on an upper frame and lower frame of molded steel plate. Crimping spots for the upright crosspieces are cut away in these through-holes and expanded outward, engaging with the cylindrical flanges of the upper frame and lower frame. The upright crosspieces and the upper and lower frames are held in place by this engagement part and by bulges provided on the outer upright crosspieces of the through-holes.
In the prior art described above, because the oil strainer pipe member and umbrella-shaped member are joined and held in place with a reinforcement, there is the problem that the number of parts and the attachment operations are increased by the portion attributable to the reinforcement, and the running costs of the equipment itself are that much higher. Because the pipe member, umbrella-shaped member, and reinforcement are joined by welding, there is the additional problem that the process of manufacturing the oil strainer is more complicated. If the reinforcement is omitted, the strength of the joint between the pipe member and the umbrella-shaped member is reduced.
Also, with the crimping member and crimping structure disclosed in examined patent HEI 7-4631 1995!, the application of excessive force to the flange formed in the crimping member or to the corresponding member that is fitted into the crimping member may cause a crack in the connecting hole of the correspondent member, of the same diameter as the cylindrical part. There is the further problem that the corresponding member cannot be made thinner in order to avoid such cracking.
In the first plate and second plate anchoring structure disclosed in examined utility model HEI 5-22344 1993!, crimping is formed surrounding the flat rib on the cylindrical protrusion of the first plate located on the inner side and the flat rib on the crimping cylinder of the second plate located on the outer side, holding the two plates in place. But there is the problem that the cylindrical protrusion of the first plate may be curved. If the cylindrical protrusion is long, it is difficult to form the flat rib. Also, because the crimping part of the first plate and second plate overlap, the crimping to this extent bulges outward, creating the problem that more space is needed and the freedom of design is restricted.
Also, with the fence as disclosed in unexamined utility model SHO 58-71422 1983!, both ends of multiple upright crosspieces are inserted into flanged through-holes on the upper and lower frames, the ends of the crosspieces are expanded open in these through-holes, engaging the cylindrical flange, and the upper and lower frames and the upright crosspieces are held in place by this engagement part and by the bulge that is formed in the upright crosspieces located outside the through-holes. There is a problem with strength, because the crimping is not done in such a way that both the ends of the upright crosspieces and the cylindrical flange of the upper and lower frames curl inward.